1. Field of the Invention
The present invention relates to a laser level, and more particularly to a laser level with improved leveling adjustability.
2. Description of the Prior Art
Because of excellent linearity, a laser level is commonly used to measure or verify the horizontality or perpendicularity of an object by emitting and receiving a laser beam. As the cost of laser transmitter decreases ceaselessly, the laser level is getting more and more common in architecture/construction projects or installation of large machines.
A conventional laser level generally comprises a level-adjusting device and a laser transmitter mounted on the level-adjusting device. The level-adjusting device adjusts the leveling of the laser transmitter whereby the laser transmitter can project a laser beam in a correct direction.
The level-adjusting device can do direction adjustment in either an active manner or a passive manner. In passive adjustment, leveling adjustment is done by means of gravitation or buoyancy of liquid, while in active adjustment, adjustment of leveling is performed through mechanical driving.
FIGS. 1-3 of the attached drawings illustrate a conventional level-adjusting device 110 for adjusting leveling of an object 116, such as a laser transmitter, mounted thereon. The level-adjusting device 110 comprises a base 113, a plurality of posts 111 extending upright from the base 113, a mounting plate 112 supported by the posts 111, a rotatable spherical body 114 mounted in an opening defined in the mounting plate 112, and a shaft 115 extending through the spherical body 114, connected to the object 116, and driven by a motor 118 so as to permit rotation of the object 116 upon actuation of the motor 118. The shaft 115, together with the object 116, is slightly moved relative to a horizontal plane, i.e. the sea level, upon rotation of the spherical body 114 during level adjustment of the object 116.
The spherical body 114 is rotated by a transmission unit 200 that comprises a mounting seat 117 connected to the spherical body 114, a connecting member 201 connected to the mounting seat 117 and having two opposite legs 211, a first operating rod 208 engageable with one of the legs 211 for driving the connecting member 201 to move in a first horizontal direction and engageable with the other of the legs 211 for driving the connecting member 201 to move in a first opposite direction opposite to the first horizontal direction, and a second operating rod 209 engageable with one of the legs 211 for driving the connecting member 201 to move in a second horizontal direction and engageable with the other of the legs 211 for driving the connecting member 201 to move in a second opposite direction opposite to the second horizontal direction.
The first and second operating rods 208, 209 are mounted slidably on a support 203 through first and second threaded blocks 207, 205 and first and second screw rods 206, 204, which engage, threadedly and respectively, the first and second threaded blocks 207, 205. In operation, movement of the first or second operating rod 208, 209 or both the first and second operating rods 208, 209 results in rotation of the spherical body 114, which, in turn, results in co-movement of the object 116 and the shaft 115 to the sea level.
The aforesaid conventional level-adjusting device 110 is disadvantageous in that leveling adjustment of the object 116 is time-consuming. For instance, since the spherical body 114 can only rotate about its center, movement of the first operating rod 208 not only results in movement of the connecting member 201 in the first horizontal direction, but also results in an undesired movement of the transmission member 201 in the second horizontal direction due to rotation of the spherical body 114, which requires further operation of the second operating rod 209 to adjust leveling of the object 116, which, in turn, requires further operation of the first operating rod 208, and so on. As a consequence, the operation is quite time-consuming.
Hence, an adjusting device is required to overcome the above-mentioned disadvantages of the prior art.